1. Field of the Invention
The present invention relates to a recording/reproducing device using a recording/reproducing disk such as a floppy disk and a hard disk and, more particularly, to a structure for mounting a flexible printed circuit board (hereinafter referred to as FPC) for transmitting a signal to a magnetic head, and a recording/reproducing device using the same.
2. Description of Related Art
A recording/reproducing device using a conventional structure for installing an FPC, as shown in FIG. 11, is provided with a square through hole 51c in the corner section of a chassis 51 made of a metal plate. Below the chassis 51, a printed circuit board 52 is attached to partly cover the underside thereof.
The printed circuit board 52 has a couple of long mounting holes 52a in the corner section. On the underside of the printed circuit board 52, a circuit pattern 52b (FIG. 12) is provided. On the chassis 51, a head device 55 is located for writing an information signal into, or reading an information signal from, an unillustrated magnetic disk. The head device 55 has a carriage 56 which can reciprocate in the direction (in the direction of the arrow A in the drawing) of magnetic disk insertion or removal. The carriage 56 is comprised of a head mounting base 56a located below, and an upwardly slidable head support arm 57. At the forward end of the head mounting base 56a and the head support arm 57, a pair of magnetic head 58 are mounted in mutually opposite positions.
The pair of magnetic heads 58 are connected with one end of the FPC""s 60 and 61; the other ends of the FPC""s 60 and 61 are free ends.
On the free end side of the FPC""s 60 and 61, terminal portion 60a and 61a are formed in an exposed state.
An FPC holder 62 is a member made of a resin having a U-shaped cross section, and is provided with lower end portions 62b and 62c projecting downwardly for insertion into the through hole 51a of the chassis 51.
In the FPC""s 60 and 61 connected to the pair of magnetic head 58, the terminal portions 60a and 61a on the free end side thereof are attached to the FPC holder 62, and fitted to the mounting hole 52a of the printed circuit board 52, being connected to the circuit pattern 52b (FIG. 12). As shown in FIG. 12, the FPC holder 62 fitted with a couple of FPC""s 60 and 61 is inserted through the through hole 51a of the chassis 51, with the lower end portions 62b and 62c of the FPC holder 62 inserted in the mounting hole 52a of the printed circuit board 52.
The terminal portions 60a and 61a of the FPC""s 60 and 61 and the circuit pattern 52b on the printed circuit board 52 are fixedly attached and electrically conducted by solder 63.
The recording/reproducing device 50 using the mounting structure of the FPC""s 60 and 61 has a drawing: if the FPC holder 62 has an excess play when the FPC""s 60 and 61 are soldered to the printed circuit board, either one or both of the terminal portions 60a and 61a of the FPC""s 60 and 61 will fail to deviate from the position of the circuit pattern 52b of the printed circuit board 52, resulting in defective soldering of both or either one of the FPC""s 60 and 61.
As an example of improvement effected to solve the problem of defective soldering, a recording/reproducing device 70 using the FPC mounting structure proposed by the applicant will be described with reference to FIGS. 13 and 14.
The printed circuit board 72 is provided with long mounting holes 72a, 72a formed as shown in FIG. 13.
The same number of guide holes 51a and 51b as the number of the FPC holders 82 are formed mutually adjacently into an about long-hole shape.
The chassis 51 has support projections 51c and 51e formed by cutting and raising a part of the guide holes 51a and 51b. These support projections 51c and 51e are formed in mutually deviated positions so that extensions prior to cutting and raising will not be overlapped with each other.
On the forward end of FPC""s 80 and 81 a plurality of terminal portions 80a and 81a formed of a copper foil or other are exposed on the lower side. On the upper side of the terminal portions 80a and 81a, a circuit pattern extended into the base sections 80c and 81c of the FPC""s 80 and 81 is routed in a laminate shape. The end portion on the base sections 80c and 81c side of the FPC""s 80 and 81 is connected to the magnetic head 58.
On the back side of the FPC""s 80 and 81 where the terminal portions 80a and 81a are not exposed, a double-faced adhesive tape is affixed, by which the FPC""s 80 and 81 are attached to a later-described FPC holder 82.
The FPC holder 82 is a resinous member generally formed in a flat-plate shape. At the center of its one side, an approximately rectangular projecting portion 82a is formed projecting outwardly. The lower part of the projecting portion 82a is tapered. The lower end portion 82b is disposed to the lower portion, and terminal portions 80a and 81a of the FPC""s 80 and 81 are attached.
On the lower portion of the FPC holder 82, in FIG. 13, first and second arm portions 82d and 82e are extended from the right and left sides in the direction of a central projecting portion 82a. 
In the drawing, on the right side surface of the FPC holder 82 an elastically deformable hook-shaped retaining portion 82g is formed.
Furthermore, at the lower corners of the FPC holder 82, guide portions 82h and 82j are formed for positioning the terminal portions 80a and 81a of the FPC""s 80 and 81. The terminal portions 80a and 81a positioned by the guide portions 82h and 82j are attached by a double-faced adhesive tape on the FPC holder 82.
The forward end of the FPC""s 80 and 81 is bonded on the FPC holder 82. To attach this FPC holder 82 to the printed circuit board 72, the lower end portion 82b of the FPC holder 82 is inserted into the guide holes 51a and 51b of the chassis 51, and the portion between the first and second arm portions 82d and 82e is fitted on the support projections 51c and 51e. And also the lower end portion 82b of the FPC holder 82 and the terminal portions 80a and 81a are inserted in position in the mounting hole 72a of the printed circuit board 72, thereby aligning the terminal portions 80a and 81a with the circuit pattern of the printed circuit board 72.
The guide portions 82h and 82j of the FPC holder 82 are brought into contact with the surface of the printed circuit board 72, so that the insertion of the FPC holder 82 into the guide holes 51a and 51b and the mounting hole 72a stops thereat.
At this time, the retaining portions 82g, 82g are snapped into engagement with the guide holes 51a and 51b. The FPC holder 82 is fixedly retained in the guide holes 51a and 51b. 
With the FPC holder 82 thus snapped into engagement with the guide holes 51a and 51b, the terminal portions 80a and 81a of the FPC""s 80 and 81 protruding out of mounting hole 72a of the printed circuit board 72 and the circuit pattern of the printed circuit board 72 are connected by solder 63, to thereby electrically conduct the terminal portions 80a and 81a and the circuit pattern of the printed circuit board 72, thus assembling the mounting structure of the FPC""s 80 and 81.
In the recording/reproducing device 70 using the FPC 80 and 81 mounting structure proposed, there will be left a 0.1 mm or larger clearance between the FPC holder 82 and the terminal portions 80a and 81a located in the mounting hole 72a of the printed circuit board 72. The solder 63 will flow into this clearance, failing in substantially securely attaching to a proper strength by soldering.
Therefore, it is likely that the terminal portions 80a and 81a of the FPC""s 80 and 81 and the circuit pattern of the printed circuit board 72 can not reliably be electrically connected.
It is, therefore, an object of the present invention to provide an FPC mounting structure capable of easy soldering without producing a clearance between the FPC and the printed circuit board, and a recording/reproducing device using the same.
As a first means for solving at least one of the above problems, the present invention has a flexible printed circuit board having a terminal portion forming portion at which a terminal portion is formed in an exposed state on one side of the forward end an FPC holder having an elastic portion on the surface side and capable of mounting the terminal forming portion on the back side, a printed circuit board having a mounting hole, and a chassis located above the printed circuit board and having a guide hole for inserting the terminal portion into the mounting hole of the printed circuit board; the chassis being provided with a support projection formed by cutting and raising the edge portion of the guide hole. The FPC holder fitted with the terminal forming portion is inserted into the guide hole to elastically hold the elastic portion of the FPC holder in contact with the support projection, thereby pressing the terminal portion of the FPC against the edge portion of the printed circuit board mounting hole.
Furthermore, as a second means for solving the problem, the elastic portion is provided with an retaining engagement projection for preventing disengagement on the lower end of the FPC holder.
Furthermore, as a third means for solving the problem, the present invention uses the aforesaid flexible printed circuit board mounting structure.
The foregoing object and other objects, features and advantages of the present invention will become more apparent and understandable from the following detailed description thereof, when read in connection with the accompanying drawings.